Diagnosis: A member of the genus Dipsas characterised by 15 dorsal scale rows, the mid-dorsal row slightly enlarged; four pairs of chin-shields, the first pair elongate; elongate loreal entering orbit; one preocular; six upper labials, with only one elongate upper labial posterior to those that enter the orbit; head narrow anteriorly, increasing in width posteriorly; eye visible from below. The new species can be referred to Dipsas because it possesses the following suite of characters: head distinct from neck; mental groove absent; tertiary temporals present; four pairs chinshields; posterior chinshields separated from lower labials by other scales; maxillary teeth angled inwards; pterygoids parallel, not diverging posteriorly; occurring in northern South America (Peters 1960).Dipsas pakaraima can be distinguished from D. catesbyi by its 15 dorsal scale rows (13 in D. catesbyi), six upper labials (8-9), loreal entering orbit (not); from D. copei by four pairs of chinshields (three in D. copei), six upper labials (10-11), loreal entering orbit (not); from D. indica and D. pavonina by 15 scale rows (13 in D. indica and D. pavonina), six upper labials (9-11), four pairs of chin-shields (three); from D. variegata by one preocular (none in D. variegata), six upper labials (7-10), four pairs of chinshields (two or three). No other described species of Dipsas occurs in the Guiana region.

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Etymology

The specific epithet refers to the Pakaraima Mountains of western Guyana, where the type locality is located. It is used as a noun in apposition.